Inflatable cellular assemblies of plastic material

ABSTRACT

Pneumatic structural and cushioning material of plastic sheets, bands, and/or tubes, which are compartmentized into a plurality of chambers. The material is capable of convenient and economical storage and shipment in a collapsed state and rapid inflation to an operative state at the point of use. The chambers embody one-way valving arrangements to maintain the chambers in an expanded state over long periods of time, rendering the product useful in cushioning loads during shipment by land, air or water; in safety devices for humans in vehicle bumpers, air cuhsins, and buoyant devices of all types; and in structural assemblies of either temporary or permanent types to attain heat and sound insulation effects.

This invention relates to the production of inflatable cellularassemblies of plastic material, adapted to be filled with air or othergas to attain cushioning or other effects, which may be used in manyindustrial fields for different purposes.

It is the object of the present invention to improve the production ofquilted laminated plastic sheets and bands which are economical toproduce and which may be conveniently stored and shipped preparatory totheir ultimate handling at the point of use to render them effective fortheir intended purposes.

It is another object of the invention to simplify the manufacturingprocedures in the production of laminated plastic sheets which areadapted to be inflated for use at their ultimate destination by means ofself-sealing valving arrangements which are incorporated in thelaminated sheeting, which are effective at varying degrees of inflationin dependence upon the specific needs to be served, and which remaineffective for their intended purposes over long periods of time.

It is another object of the invention to produce effective andeconomical pneumatic cushioning material from plastic sheets and tubing,which is compartmentized into multiple cells or chambers to provideclean and effective substitutes for loose dunnage used in the cushioningof articles against damage by shock or blows when such are shipped byrail, airplane or auto vehicles.

More specifically, it is the object of the present invention to simplifythe production of laminated plastic sheeting subdivided into a pluralityof sealed air-filled chambers which present improvements over thepractices in the prior art as exemplified by U.S. Pat. Nos. 3,011,930,Dec. 5, 1961; 3,660,189, May 2, 1972; 3,868,285, Feb. 25, 1975, andothers.

The invention herein is useful not only for the production of cushioningmaterial but also for multi-cellular gas-filled assemblies which may beuseful in temporary or permanent building structures and in theattainment of heat and sound insulation effects therein, as well as invehicles and other structures, as well as for safety devices such as aircushions, vehicle bumpers and the like.

Other objects and purposes will appear from the detailed description ofthe invention following hereinafter, taken in conjunction with theaccompanying drawings, wherein

FIG. 1 is a perspective view of the separate components of a basicembodiment of the invention, featuring automatically operating valvingarrangements for the discrete gas chambers forming the essential part ofthe invention;

FIG. 2 is a plan view of the assembled embodiment shown in FIG. 1;

FIG. 3 is a front elevation of FIG. 2;

FIGS. 4 and 5 are vertical sectional views along line 5--5 of FIG. 2,the former illustrating the interconnection of the plastic sheets withthe valve openings therein in the course of filling the gas chambers,and the latter illustrating the position of the parts at the end of theinjection of the gas into the chambers;

FIG. 6 is a longitudinal sectional view of FIG. 2, illustrating theeffect of the incoming gas on the series of chambers in the course ofthe filling operation illustrated in FIG. 4, and preparatory to theassumption of the parts shown in FIG. 5 when the air injection isstopped at any desired degree of inflation;

FIG. 7 illustrates a second embodiment of the invention starting with aportion of a length of plastic sheeting which is contoured for thefabrication of a double set of opposed air chambers of the type shown inFIG. 1;

FIGS. 8 to 11 are perspective views illustrating the procedural stepsfor converting the originally formed plastic sheeting shown in FIG. 7 tothe assembly shown in FIG. 11;

FIG. 12 is a perspective view of still another embodiment of theinvention for producing a string of gas cells or chambers with valvingarrangements incorporated therein;

FIG. 13 is a vertical sectional view along line 13--13 of FIG. 12;

FIG. 14 is a perspective view of another embodiment of the invention forattaining a string of gas chambers along a specially molded centralcore;

FIG. 15 is a horizontal sectional view along line 15--15 of FIG. 14;

FIG. 16 is a perspective view of still another embodiment of a string ofsealed gas chambers surrounding a tubular core; and

FIG. 17 is a sectional view along line 17--17 of FIG. 16.

The first embodiment of the invention is illustrated in simplified formin FIGS. 1 to 6 of the drawings. The cushioning unit 10 is preferablyformed of four laminations. The uppermost sheet 1 is a thermoplasticpolymeric film such as polyethelene, polypropylene, polyesters, nylon,polyvinyl chloride, polyvinylidene, polyurethane, etc., having athickness which may range from 0.3 mil to 5 mil. or more, depending uponthe intended use of the material which, of course, is gas impervious aswell as abrasion and wear resistant.

Walls 5, to outline the gas chambers, are pre-formed in the sheet 1 byheat and/or vacuum, so that these may be collapsed or distended by gaspressure, and the boundaries of these are sealed by heat, solvents oradhesive to at least one underlying planar sheet of plastic material.Thus, the opposite edges and the transverse or cross-seals 12 serve toeffect adhesion of the sheet 1 to the underlying thermoplastic sheets 2and 3, which are thinner than sheet 1, along the longitudinal edges11,11' and the transverse or cross-seals 12 extending between the edgeswhich compartmentize the sheet into a plurality of chambers 5. Sheets 2and 3 are provided with rows of apertures 2' and 3', respectively, alongdisplaced lines of the sheets 2 and 3, and preferably the apertures 2'of sheet 2 are smaller than the apertures 3' in sheet 3.

The base outer sheet 4, which is thicker than the sheets 2 and 3 andwhich is both wear-resistant as well as gas-impervious, underlies theassembly of sheets 1, 2 and 3, and is sealed along the longitudinaledges 11,11' as well as at the end 13. The opposite end 14 is open forthe admission of a gas under pressure into the laminated assemblythrough tube 15 which, as illustrated in FIGS. 4 and 6 permits the gasto pass through the openings 3' in sheet 3 and thereafter throughapertures 2' in sheet 2 for entry into the several bubbles or chambers5. The thinned molded plastic protrusions 5 may be collapsed to exhaustthe air therefrom through apertures 2' and 3' and the flattened sheetmay be folded or rolled until it is ready for use. When this is done byconnecting an injecting tube 15 to the inlet end, as shown in FIG. 6,the flattened protrusions become partially or fully extended, and whenthe pressures in these chambers exceed that of the incoming air, andcertainly at any time when the gas inlet tube 15 is removed from theassembly, the portion of the sheet 2 with the openings 2' are forcedinto contact with the solid portion of the sheet 3 therebelow to sealoff the egress of the gas from the respective chambers, at any degree oftheir inflation. Furthermore, the solid area of sheet 2 is pressedagainst the series of apertures 3' in the underlying sheet 3 to closethese openings against egress of air, whereupon the assembly isdistended for contact with the articles sought to be protected eithersimultaneously with the gas injection into the assembly, or thereafter,to prevent their movement and eventual breakage and shock. Thesimultaneous distension of the gas bubbles and contact cushioning of thearticles is practiced in those instances where it is desirable todispose the cushioning strip in its collapsed state around the articlesbeing protected and to inflate the bubbles 5 to any necessary degree toattain differential cushioning effects, depending upon the variablecontours of the articles being protected.

While the base sheet 4 may be of thermoplastic sheet material, as arethe other layers, the purposes of the invention may be served if such isformed of semi-rigid material such as cardboard which is impregnatedwith a plastic or wax to render it gas impervious as well as adherent tothe superposed layers 1, 2 and 3 along the longitudinal edges by meansof heat, adhesive, etc. Furthermore, the advantages of the invention maybe realized to a less effective degree by the use of a singleintermediate sheet, in lieu of two sheets 2 and 3, which is pressed bythe preponderant pressure in the chambers 5 against the solid base layer4, below the intermediate sheet with the valve openings therein.

Also, apertures 3' in sheet 3 may be of the same size as the apertures2' in sheet 2 without affecting deleteriously the valving functionsperformed thereby.

While FIG. 1 shows a single row of distendable chambers 5, it isunderstood that the invention may be applied to large areas of plasticsheets to form these extensible chambers along multiple longitudinalrows as well as transverse rows as is commonly known in the art andillustrated in the patents mentioned above.

Another embodiment of the invention is shown in FIGS. 7 to 11 to form aseries of gas chambers on opposite faces of a base sheet of plastic. Inthis construction, a sheet 20 of thermoplastic material is shaped with apair of troughs or valleys 21,22 by vacuum, or vacuum with heat molding,with an intermediate planar edge 25 between them, and the outer planaredge 23 adjacent through 21 and an outer planar edge 24 adjacent trough22. The wear-resistant unit 20 is superposed by a thinner sheet ofthermoplastic material 30, which is sealed to the former by heat,adhesive or solvent at the opposite edges 23' and 24', and at theintermediate portion 25', to the above-mentioned planar edges 23, 24 and25, respectively. The sheet 30 is also provided with a plurality of rowsof apertures 27 and 28 overlying the troughs 21 and 22, respectively,preferably in corresponding positions, so that when the troughs areflapped over each other, around the longitudinal median 25, 25 as anaxis, as clearly shown in FIGS. 10 and 11, the apertures will bedisposed in non-aligned rows.

FIG. 9 shows the obverse position of the sheets 20 and 30 andillustrates the transverse or cross-seals 35 which convert thelongitudinal troughs 21 and 22 into a plurality of rectangular pyramidalbubbles, to function as gas chambers 31 and 32, respectively. Theassembly shown in FIG. 9 is folded longitudinally along the seam 25,25'to dispose the gas chambers 32 below the gas chambers 31, and the outeredges 23 and 24 are sealed in any suitable manner which, in conjunctionwith the integral seal 25,25' results in an assembly as shown in FIG. 11wherein the gas chambers 31 superpose the gas chambers 32, at which timethe air may be pressed therefrom for egress through apertures 27 and 28and the space between portions of sheet 30, followed by the folding orrolling of the assembly upon a reel to provide a very compact mode ofstorage or shipment.

When the material is intended to be used, pressurized air is introducedinto the space between juxtaposed folded surfaces of sheet 30, so that aportion thereof will pass through the apertures 27 to inflate the gaschambers 31 while another portion thereof will pass through theapertures 28 to inflate the chambers 32 to any desired degree. When thegas pressure in the chambers rises to a sufficient degree which exceedsthe pressure of the incoming gas, the relatively thin plastic sheeting30 will be pressed into contact with the adjacent portion of the samesheeting to close off the apertures 27 and 28. This would be the casewhen the source of gas pressure is removed from the space between thetwo superposed layers of sheet 30.

As described above, the embodiment of the invention illustrated in FIGS.7 to 11, features a single pair of troughs superposed by a sheet ofplastic with valve openings therein. If desired, the shaped or stretchedsheet 20 may be formed with any number of rows of troughs which may becovered by the planar thin sheet of thermoplastic material 30, and asimilar assembly could be superposed thereupon as long as the outer andintermediate edges are sealed longitudinally similarly to the edges23,23', 24,24' and 25,25', which is followed by the transverse sealingof the multiple rows to form large areas of air chambers 31 and 32.Alternatively, cushioning material of large areas with multiple rows ofdistendable gas chambers could be formed by providing multiple pairs oftroughs and folding over one symmetrical portion over the other andsealing the longitudinal edges between the rows in a manner similar tothat illustrated in FIGS. 7 to 11 with a single pair of troughs. In allof the variant forms described above, the rows of apertures 27 and 28 inthe respective overlying rows of air bubbles must be out of alignment toattain a seal against the adjacent sheets.

A variant embodiment of the invention, with an automatically operatingvalving arrangement similar to those described above, is illustrated inFIGS. 12 and 13. In this case, a self-sustaining tubular core ofthermoplastic material 40 is provided with a plurality of apertures 41along the length thereof. Surrounding it is a sheet of thin plasticmaterial which may be sealed at the outer edges 44 or which may be ofintegral tubular formation. A row of apertures 43 is provided in tube 42which is offset from the apertures 41, and surrounding theabove-mentioned tubes 40 and 42 is a sheet 45 of rugged andgas-impervious thermoplastic material, the opposite ends of which may bejoined along a longitudinal seam 46, or which may be of integral tubularformation. The outer wear-resistant tube of plastic is compartmentizedinto a series of bubbles or gas chambers by heat sealing longitudinallydisplaced portions 47 of the tube 45 to the inner tube 42 and thecentral tube 40. This may be done by a pair of heated jaws which areprovided with aligned semi-cylindrical recesses of a diameter toaccommodate tube 40 and the layers of plastic sheeting surrounding it toeffect their coalescence at displaced points 47. The air in the chambersmay be exhausted before this sealing operation, or the air may beexhausted from the individual chambers by merely squeezing on the outerchambers so that the air passes therefrom through the openings 43 andopenings 41 through the interior of the core to one or both ends untilone of these is sealed to make possible the injection of compressed airinto the other one. The assembly can be maintained in reeled form untilrequired for use, when it is packed around articles to be protectedagainst shock, followed by the injection of a gas into the open end oftube 40 and the string of bubbles surrounding it. The individual gaschambers become filled with the gas entering through apertures 41 andopenings 43 until such time as the gas pressure on the interior of thechambers will press the thin sheet of plastic 42 against the lateralsurface of the central core 40 to arrest the egress of the gas from theindividual chambers.

FIGS. 14 and 15 disclose another embodiment of the invention whichfeatures an enlarged core 50 formed of extruded thermoplastic materialhaving a special cross-section characterized by a longitudinal bore 51through its thickest portion and a bifurcated or slotted flangeextending from the core 50. The flange is constituted by superposed arms55 and 56 to form a slot 57 therebetween. The core 50 of the extrusionis flattened in the plane of the slot 57 and a plurality of passages 52extend from the central bore to the exterior thereof. One edge of aflexible strip 69 of plastic is inserted into the slot 57 and theopposite edge thereof overlies the flattened outer surface of the coremember 50 and the openings 52 in the latter. The latter edge is ofcastellated outline formed by rectangular notches 59 between rectangularportions 60 (FIG. 15). The portions 60 serve as flap valves foralternatively covering and uncovering the passages 52 leading from theinterior of the tubular core member. These flap valve portions 60 aresectionalized by surrounding the core 50 and strip 69 with a sheet 65 ofwear-resistant thermoplastic material and shaping it into tubular formby sealing its opposite edges 66 and 67 to the outer faces of the arms55 and 56 of the slotted flange and heat-sealing the entire assembly atlongitudinally displaced points 70 to subdivide the latter into aplurality of inflatable air chambers. The cross-seals 70 include theflexible sheet of plastic 69 at the narrowed portions 59 which, ineffect, form the separable individual flap valves in each of thechambers for the passages 52. Thus, air injected under pressure at oneend of the bore opening 51 is admitted into the individual chambers 65by the lifting of the flap valve 60 in each chamber from the openings 52below it. When the pressure in the gas chambers exceeds the pressure ofthe incoming gas, the flap valves close, to seal off the egress of thegas therefrom to permit the assembly to remain in its inflated state.

If desired, the outer wear-resistant tube may be of integralconstruction with a circumferential portion thereof sealed to the outerfaces of arms 55 and 56 with the remainder fitting the core loosely,except at the seal points 70 where the tube 65 is integrated in itsentirety to the exterior of the core, slotted flange and the plasticstrip retained thereby.

Another embodiment of the invention for forming a string of gas chambersalong a central core is illustrated in FIGS. 16 and 17. In thisconstruction, a self-sustaining tube 80 of thermoplastic material isprovided with one or more openings 81 at longitudinally displacedopenings along the length of the tubular core. These openings arecovered with a fast drying liquid coating 83 which is flexible andoperates as a closure valve for the openings 81. This elastic materialmay be a silicone rubber such as RTV rubber which conforms to the shapeof the tube and which will be cured upon its application thereto so thatit may exert a valving action on the openings. Similar effects may beattained with movable tubular covers for the valve opening formed of"Saran" sheeting, polyvinyl chloride, copolymer films, etc.

A sheet 85 of rugged thermoplastic material surrounds the central corewith the special valving assemblies 83 along the length thereof, and thesheet may be sealed along the longitudinal edges 86 to form the tubularencasement around the central core 80. Alternatively an integral tube ofthermoplastic material may be used to enclose the central core, and ineither case, cross-seals 87 are applied to the to the tubular casings tosectionalize the outer tube into a plurality of chambers. The injectionof compressed air or any other suitable gas under pressure into one endof the central core 80 against the opposite end which is sealed, willserve to force air into the several chambers 85 by the lifting of theflexible plastic closures 83 from the openings 81 to admit the gas intothe chambers until such time as the pressure in the latter predominatesover the pressure of the incoming gas. The gas chambers remain in aninflated state as long as this condition prevails, and, of course,whenever the injection of gas into the assembly is arrested.

Depending upon the ruggedness of the outer tubular sheets or tubes, thegas chambers may be used in many different industrial locales and forpurposes other than the cushioning of packaging material. Suchapplications include heat and sound insulation, and safety systems forboth articles and humans, such as vehicle bumpers, buoyant safetydevices an apparel for water sports, etc.

We claim:
 1. An inflatable laminated pad of plastic sheet material,comprising(a) an elongated outer wear-resistant sheet of plasticmaterial provided with a plurality of discrete collapsed but extensiblebubbles along the length thereof, (b) a second elongated outerwear-resistant sheet of plastic material sealed to said first sheetalong the longitudinal edges common to both sheets, whereby theinjection of a compressed gas into the space between said sheets effectsthe distension of said bubbles, and (c) at least one intermediate layerof thin apertured plastic sheeting between said outer layers to permitthe expansion of said bubbles to a degree sufficient to build up apressure of such intensity on the solid areas of said intermediate layeras will force said apertured layer into contact with said second sheetto seal off the communication between said outer sheets when the gaspressure is removed from the inner face of said second outer sheet. 2.An article as set forth in claim 1, including two intermediate layers ofthin plastic sheeting each provided with a row of apertures extending inparallel to said longitudinal edges but out of alignment with eachother.
 3. An article as set forth in claim 2, wherein said rows ofapertures are adjacent to but displaced from said longitudinal edges. 4.An inflatable continuous laminated pad of plastic sheet material,comprising(a) an elongated sheet of wear-resistant plastic materialshaped into two longitudinally extending juxtaposed troughs with planarouter and intermediate edges, (b) a cover of thin sheet plastic materialsealed to said first-mentioned sheet at said planar edges and providedwith rows of apertures, which upon folding over each other at saidintermediate edge become laterally displaced, (c) transverse sealsbetween said first-mentioned sheet and cover at longitudinally displacedpoints to compartmentize the latter into a plurality of separatechambers, whereby the injection of a compressed gas into the spacebetween the juxtaposed layers of the folded cover sheet effects thedistention of said chambers by the passage of the gas through saiddisplaced rows of apertures, which are adapted to be closed by theadjacent full surface portion of the cover when the pressure engenderedin the chambers is sufficient to force the apertured portion of thecover against said full surface portion.
 5. An article as set forth inclaim 4, wherein said rows of apertures are in the same correspondingposition adjacent to an edge of each trough, prior to the folding overeach other.
 6. An inflatable continuous laminated pad of plastic sheetmaterial, comprising(a) an assembly of an elongated sheet ofwear-resistant plastic material shaped into a plurality oflongitudinally extending juxtaposed troughs with planar outer andintermediate edges, (b) a cover of thin sheet plastic material sealed tosaid first-mentioned sheet at said planar edges and provided with rowsof apertures overlying each of said troughs and displaced from thelongitudinal centers thereof, and (c) transverse seals between saidfirst-mentioned sheet and cover at longitudinally displaced points tocompartmentize the latter into a plurality of separate chambers, (d) asecond assembly identical to said first-mentioned assembly sealed toeach other in allochiral relation at one end and along said outerlongitudinal edges only with said covers in juxtaposition, to form aspace therebetween for the injection of a compressed gas thereinto toeffect the distention of said chambers by the passage of the gas throughsaid displaced rows of apertures, which are adapted to be closed by theadjacent full surface portion of the adjacent cover when the pressureengendered in the chambers is sufficient to force the apertured portionof the respective cover against said full surface portion of the othercover.
 7. A continuous length of inflatable chambers of plastic sheetmaterial, comprising(a) a self-sustaining tubular core member sealed atone end and having a plurality of apertures along the length thereof,(b) a thin tubular sheet of plastic material surrounding said memberhaving a plurality of openings along the length thereof displacedradially from said first-mentioned apertures, (c) a tubular casing ofair-impermeable plastic sheet material surrounding said member and outertubular sheet and sealed together at longitudinally displaced pointswhich include a plurality of said apertures and openings, to define saidchambers, adapted to be distended by the injection of a compressed gasinto the open end of said member for passage into said chambers throughsaid apertures and openings, and which, upon the cessation thereof, aresealed in an inflated state by the stoppage of gas from said chambers,in consequence of the pressure therein effecting the closure of theopenings in the thin tubular sheet by pressure against said tubular coremember.
 8. An article as set forth in claim 7, wherein said apertures insaid tubular core and said openings in said tubular sheet are arrangedin straight rows which are displaced radially from each other.
 9. Acontinuous length of inflatable chambers of plastic sheet material,comprising(a) a hollow core member of plastic material sealed at one endand having a flattened outer surface with a slotted flange extendingoutwardly from said surface, said core member being provided with aplurality of apertures between said surface and the interior of saidcore member, (b) a strip of plastic sheeting in the slot of said flangeoverlying said flattened outer surface with one edge thereof within theslot of said flange and the opposite edge thereof of castellatedoutline, (c) an air-impermeable plastic sheet encasing said hollow coremember and adapted to have the opposite longitudinal edges thereofsealed to the exterior of said flange to form a confining spacetherearound, (d) a plurality of transverse seals at longitudinallydisplaced points of said plastic sheet and coincident with the reducedwidths of the strip to compartmentize said space into a plurality ofseparate chambers, with the strip adjacent the free edges thereoffunctioning as flap valves for said apertures, (e) said chambers adaptedto be distended by the injection of a compressed gas into the open endof said hollow member for passage into said chambers through saidapertures, and which, upon cessation of said injection, are sealed in aninflated state by the stoppage of gas from said chambers in consequenceof the pressure therein acting on the flap valves to close the aperturesin said hollow core member.
 10. A continuous length of inflatablechambers of plastic sheet material, comprising(a) a self-sustainingtubular core member sealed at one end and having a plurality ofapertures at longitudinally displaced points along the length thereof,(b) flexible and distendable coverings of plastic material overlyingsaid apertures, (c) a tubular casing of air-impermeable plastic sheetmaterial surrounding said member and sealed thereto at longitudinallydisplaced points between said apertures to define said chambers, adaptedto be expanded by the injection of a compressed gas into the open end ofsaid member for passage into said chambers through said apertures uponthe distention of said surrounding covering, and which, upon thecessation of said injection, are sealed in an inflated state by thestoppage of gas into said chambers, in consequence of the pressuretherein on said coverings against said tubular core member to close saidapertures.
 11. A device as set forth in claim 10, wherein said flexiblecoverings are formed by a fast-drying elastomeric coating solution.